var a=[1,2,3,5,40]
a.unshift(10)
console.log(a);

var arr=[{name:'zs',age:10},{name:'li',age:10},{name:'wa',age:10},]
// var b=arr.unshift({name:'new',age:100})
// console.log(arr);
// console.log(b);//4unshift() 把一个元素添加到数组的开头，并返回数组的新长度

arr.forEach(el=>{
    el.width=400,
    el.height=600
})
console.log(arr);
